Scroll fluid machine

ABSTRACT

A scroll fluid machine includes a compressor body having a first scroll and a second scroll which form a compression chamber, a cover forming an air guiding space by covers at least a portion of the compressor body, and a blower fan supplying cooling air to at least one of the first scroll and the second scroll. A portion of the cooling air is supercharged into the intake port via the air guiding space whereby satisfactory compression efficiency is achieved with a simple configuration.

TECHNICAL FIELD

The present disclosure relates to a scroll fluid machine.

BACKGROUND

A fluid machine including a compressor that compresses gas such as airis used in various fields of an industrial world, and a scrollcompressor is known as one type thereof. In a scroll compressor,typically, a compression chamber is formed between a fixed scroll and arevolving scroll disposed to face each other, and the compressionchamber shrinks while moving toward the center with rotation of therevolving scroll whereby a pressurized gas is generated.

In this manner, in a compression cycle of a scroll compressor, since thepressure of the pressurized gas increases as the compression chamberapproaches the center, the temperature of the pressurized gas alsoincreases. In the scroll compressor, it is necessary to form an enclosedcompression chamber by combining the fixed scroll and the revolvingscroll with high accuracy. However, such an increase in temperature maycause mechanical distortion (thermal deformation) in the fixed scrolland the revolving scroll.

The scroll compressor includes a cooling means in order to suppress theincrease in temperature of the fixed scroll and the revolving scroll.For example, Patent Document 1 discloses a structure in which coolingair is generated by a blower fan connected to a driving shaft forrotating a revolving scroll and the cooling air is supplied to radiatingfin formed on a back surface of the revolving scroll and a fixed scrollthrough a duct to thereby cool the fixed scroll and the revolvingscroll.

CITATION LIST Patent Literature

Patent Document 1: JP2010-196677A

SUMMARY Technical Problem

By the way, for example, in a scroll fluid machine including this typeof scroll compressor, although outside air at the atmospheric pressureis often taken in as a compression target gas, it is effective tointroduce a supercharging means in order to realize more excellentcompression efficiency. As such a supercharging means, adding anotherblower fan for delivering outside air to an intake port of thecompressor body may be considered, for example. However, in a scrollcompressor, as in Patent Document 1, a cooling means for suppressing theincrease in temperature of the fixed scroll and the revolving scroll isnecessary, and introduction of the supercharging device in addition tosuch a cooling means may increase the size of a device and make thedevice complex, which is disadvantageous in a manufacturing cost and aninstallation space.

At least one embodiment of the present invention has been made in viewof the above-described problems, and an object thereof is to provide ascroll fluid machine capable of realizing satisfactory compressionefficiency with a simple configuration.

In Patent Document 1, an intermediate cooler for cooling a pressurizedgas generated in a low-pressure-side compression chamber is providedoutside a compressor body. In such a configuration, since it isnecessary to arrange an intermediate cooler outside the compressor body,the device size increases, and the installation space and themanufacturing cost increase.

At least one embodiment of the present invention has been made in viewof the above-described problems, and an object thereof is to provide ascroll fluid machine capable of decreasing a manufacturing cost and aninstallation space of entire facility, the scroll fluid machineincluding an intermediate cooler having a simple configuration, disposedbetween a low-pressure-side compression chamber and a high-pressure-sidecompression chamber.

By the way, in a scroll fluid machine including this type of scrollcompressor, for example, when the machine stops in the course ofoperation, a pressurized gas on a downstream side of a compressionchamber flows backward temporarily (instantaneously), and the revolvingscroll rotates in an opposite direction to generate noise. In order toprevent occurrence of such noise, a check valve for preventing backflowof a pressurized gas may be disposed on the downstream side of thecompression chamber.

However, since the usable temperature range of a check valve used forsuch use is limited due to a structure thereof, the check valve may beunable to endure high-temperature gas immediately after being dischargedfrom the compression chamber. Therefore, in a conventional typicalconfiguration, it is necessary to arrange the check valve so that thehigh-temperature pressurized gas discharged from the compression chamberpasses through the check valve after being cooled by an after-coolerwhich is an external device provided on the downstream side. In such aconfiguration, since it is necessary to arrange an after-cooler, a checkvalve, and the like outside the scroll fluid machine, the device sizeincreases, and the installation space and the manufacturing costincrease.

At least one embodiment of the present invention has been made in viewof the above-described problems, and an object thereof is to provide ascroll fluid machine capable of effectively decreasing the temperatureof discharged gas with a simple configuration.

In a scroll fluid machine including this type of scroll compressor, forexample, since the revolving scroll is rotated by the torque from thedriving shaft, the revolving scroll is more likely to be distorted thanthe fixed scroll. Therefore, in order to suppress distortion of therevolving scroll, a reinforcement structure may be provided on the backsurface of the revolving scroll to secure mechanical strength. Forexample, a rib-shaped reinforcement member provided on the back surfaceof a revolving end plate having an approximately disc shape so as toextend in one direction is used as such a reinforcement structure.

However, since such a rib-shaped reinforcement member has a convex shapeprotruding from the back surface of the revolving end plate to whichcooling air is supplied, the reinforcement member may disturb the flowof cooling air to deteriorate the cooling performance of the revolvingscroll. Moreover, although the rib-shaped reinforcement member providesa relatively effective reinforcement effect in the vicinity of thereinforcement member, it is difficult to obtain a sufficientreinforcement effect in a region distant from the reinforcement member,and the entire revolving scroll is not reinforced sufficiently.

At least one embodiment of the present invention has been made in viewof the above-described problems, and an object thereof is to provide ascroll fluid machine capable of improving the strength in a wide rangeof regions while suppressing the increase in temperature of therevolving scroll effectively.

As in Patent Document 1, typically, a plurality of radiating finsprovided in the fixed scroll and the revolving scroll as the coolingmeans for the fixed scroll and the revolving scroll are provided atequal intervals in a blowing direction of the cooling air. Therefore,although the cooling air supplied to the radiating fins has a relativelysatisfactory cooling effect on the upstream side, since the temperatureof the cooling air increases as it advances toward the downstream side,the cooling effect weakens gradually, and the cooling effect decreases.As a result, a difference in the degree of cooling occurs between theupstream side and the downstream side, and a temperature difference mayoccur on the fixed scroll and the revolving scroll. Such a temperaturedifference may cause distortion of the fixed scroll and the revolvingscroll.

At least one embodiment of the present invention has been made in viewof the above-described problems, and an object thereof is to provide ascroll fluid machine capable of obtaining a uniform cooling effect overa wide range of regions of the fixed scroll or the revolving scroll.

Solution to Problem

(1) In order to solve at least one of the problems, a scroll fluidmachine according to at least one embodiment of the present inventionincludes: a compressor body capable of compressing fluid introduced froman intake port in a compression chamber formed between a first scrolland a second scroll; a cover forming an air guiding space by covering atleast a portion of the compressor body; and a blower fan supplyingcooling air to at least one of the first scroll and the second scroll,wherein a portion of the cooling air is configured to be superchargedinto the intake port via the air guiding space.

According to the configuration of (1), a portion of the cooling airsupplied from the blower fan in order to cool the first scroll and thesecond scroll that form the compression chamber is configured to besupplied to the intake port of the compressor body. Due to this, since aportion of the cooling air used as air for cooling the first scroll andthe second scroll can be supercharged, in spite of a simpleconfiguration, it is possible to realize a scroll fluid machine capableof obtaining satisfactory compression efficiency while suppressing theincrease in temperature of the first scroll and the second scroll.

Furthermore, according to the configuration of (1), a portion of thecooling air for cooling the first scroll and the second scroll issupercharged into the intake port via the air guiding space formed bythe cover. Since the cooling air passes through the air guiding space,dynamic pressure of the cooling air is converted to static pressure andthe cooling air having the static pressure is supercharged into theintake port. Therefore, even if the amount of air blown from the blowerfan varies greatly, the cooling air can be stably supercharged into theintake port.

(2) In some embodiments, in the configuration of (1), the air guidingspace has a larger passage area than a duct for introducing outside airfrom the blower fan into the compressor body.

According to the configuration of (2), since the air guiding space has alarger passage area than the duct, it is possible to generate staticpressure satisfactorily from the dynamic pressure of the cooling airdelivered from the duct.

(3) In some embodiments, in the configuration of (1) or (2), the coverhas a curved inner wall so that the outside air introduced into the airguiding space is rectified toward the intake port.

According to the configuration of (3), the cover that forms the innerwall of the air guiding space is formed in a curved form, the coolingair introduced into the air guiding space is rectified toward the intakeport. Due to this, the cooling air supplied into the air guiding spaceis efficiently guided to the intake port and satisfactory superchargingefficiency is obtained.

(4) In some embodiments, in the configuration of any one of (1) to (3),the scroll fluid machine further includes a filter for removing aforeign material included in the outside air supercharged into theintake port.

According to the configuration of (4), by removing a foreign materialincluded in the supercharged cooling air in order to supercharge aportion of the cooling air supplied to the first scroll and the secondscroll, it is possible to prevent the foreign material from entering thecompression chamber.

(5) In some embodiments, in the configuration of (1), the scroll fluidmachine further includes a discharge pipe through which the pressurizedgas discharged from the compression chamber flows, wherein the dischargepipe is provided to penetrate the air guiding space so that thepressurized gas flowing through the discharge pipe is cooled by thecooling air introduced into the air guiding space.

According to the configuration of (5), although supercharging into theintake port is performed using the air guiding space as described above,in this case, cooling of the pressurized gas discharged from thecompression chamber can be realized using the air guiding space. Thepressurized gas generated in the compressor body is discharged through adischarge pipe provided to penetrate the air guiding space. Therefore,the pressurized gas flowing through the discharge pipe is cooled by thecooling air introduced into the air guiding space. By cooling thepressurized gas flowing through the discharge pipe using the air guidingspace provided for supercharging into the intake port in this manner, anexternal device such as an after-cooler, for example, is not necessary,and it is possible to reduce a system size and to effectively save aninstallation space and a manufacturing cost.

(6) In some embodiments, in the configuration of (5), a check valve isincluded in the discharge pipe.

In a scroll fluid machine, when the machine stops in the course ofoperation, a pressurized gas on a downstream side of a compressionchamber flows backward temporarily (instantaneously), and the revolvingscroll rotates in an opposite direction to generate noise. In order toprevent occurrence of such noise, a check valve for preventing backflowof a pressurized gas may be disposed on the downstream side of thecompression chamber. Since the usable temperature range of a check valveused for such use is limited due to a structure thereof, the check valvemay be unable to endure high-temperature gas immediately after beingdischarged from the compression chamber. However, according to theconfiguration of (6), since it is possible to decrease the temperatureof the pressurized gas flowing through the discharge pipe as describedabove, it is possible to arrange a backflow-prevention check valve inthe discharge pipe.

(7) In order to solve at least one of the problems, a scroll fluidmachine according to at least one embodiment of the present inventionincludes: a housing; a fixed scroll which is fixed to the housing and inwhich a spiral groove formed by a fixed wrap formed on a fixed end plateis blocked by a partition wall that partitions a low-pressure-sidecompression chamber and a high-pressure-side compression chamber; arevolving scroll which is accommodated in the housing so as to face thefixed scroll to form the low-pressure-side compression chamber and thehigh-pressure-side compression chamber together with the fixed scrolland is resolvable supported by a driving shaft; a cover that forms anair guiding space between the fixed scroll and the cover so that aportion of cooling air supplied to at least one of the fixed scroll andthe revolving scroll can be introduced into the air guiding space; andan intermediate cooler configured to cool pressurized gas dischargedfrom the low-pressure-side compression chamber by heat exchange with thecooling air in the air guiding space so that the cooled pressurized gasis returned to the high-pressure-side compression chamber.

According to the configuration of (7), the spiral groove formed by thefixed wrap included in the fixed scroll is partitioned by the partitionwall, whereby the low-pressure-side compression chamber and thehigh-pressure-side compression chamber are formed between the fixedscroll and the revolving scroll. Since the pressurized gas dischargedfrom the low-pressure-side compression chamber is cooled by theintermediate cooler and is then returned to the high-pressure-sidecompression chamber, the scroll fluid machine according to thisconfiguration is configured as a multi-stage compressor.

The cover forms the air guiding space to which a portion of the coolingair supplied to at least one of the fixed scroll and the revolvingscroll can be introduced. The air guiding space forms an intermediatecooler that cools the pressurized gas discharged from thelow-pressure-side compression chamber. In the intermediate cooler, thehigh-temperature pressurized gas discharged from the low-pressure-sidecompression chamber is cooled by heat exchange with the cooling air ofthe air guiding space, and the cooled pressurized gas is returned to thehigh-pressure-side compression chamber. In this manner, since theintermediate cooler capable of realizing cooling using a portion of thecooling air supplied to at least one of the fixed scroll and therevolving scroll can be formed integrally with the compressor body inthe air guiding space formed by the cover, it is possible to simplifythe configuration as compared to a conventional configuration and toeffectively reduce a manufacturing cost and an installation space ofentire facility.

(8) In some embodiments, in the configuration of (7), the intermediatecooler includes a radiating pipe arranged in the air guiding space so asto connect a low-pressure-side discharge port of the low-pressure-sidecompression chamber and a high-pressure-side inlet port of thehigh-pressure-side compression chamber.

According to the configuration of (8), the high-temperature pressurizedgas discharged from the low-pressure-side discharge port of thelow-pressure-side compression chamber is supplied to thehigh-pressure-side inlet port of the high-pressure-side compressionchamber after being cooled by heat exchange with the cooling airintroduced into the air guiding space when passing through the radiatingpipe arranged in the air guiding space.

(9) In some embodiments, in the configuration of (8), the radiating pipeis arranged to be folded back on an inner wall of the air guiding space.

According to the configuration of (9), since the radiating pipe throughwhich the high-temperature pressurized gas which is a cooling target inthe intermediate cooler flows is arranged to be folded back on the innerwall of the air guiding space, it is possible to secure a large contactarea between the radiating pipe and the cooling air introduced into theair guiding space and to obtain a satisfactory cooling effect.

(10) In some embodiments, in the configuration of (9), the radiatingpipe is configured such that a plurality of radiating portion extendingalong the cooling air are connected by a plurality of folded-backportions formed to be lower than the plurality of radiating portions.

According to the configuration of (10), since the radiating pipe has aconfiguration in which a plurality of radiating portions are connectedby a plurality of folded-back portions, it is possible to arrange a longradiating pipe in a limited compact space. Moreover, since the pluralityof radiating portions extend along the blowing direction, the radiatingportions do not disturb the flow of outside air. Furthermore, since thefolded-back portions are formed to be lower than the radiating portions,the outside air can be introduced smoothly between the adjacentradiating portions. In this manner, the radiating pipe of thisconfiguration provides a satisfactory cooling effect.

(11) In some embodiments, in the configuration of any one of (8) to(10), the low-pressure-side discharge port is disposed on a downstreamside of the cooling air as compared to the high-pressure-side inletport.

According to the configuration of (11), since the high-temperaturepressurized gas is discharged from the low-pressure-side compressionchamber in the low-pressure-side discharge port, the low-pressure-sidedischarge port is disposed on the downstream side of the cooling air ascompared to the high-pressure-side inlet port through which thelow-temperature pressurized gas cooled by the intermediate cooler flows.On the upstream side, since the cooling air is heat exchanged with thepressurized gas after being cooled by the intermediate cooler, theincrease in temperature of the cooling air is small, and a relativelylow-temperature cooling air can be supplied to the downstream side. Inthis way, it is possible to effectively cool the high-temperaturepressurized gas before being cooled by the intermediate cooler on thedownstream side.

(12) In some embodiments, in the configuration of at least one of (7) to(11), the scroll fluid machine further includes a discharge pipe throughwhich the pressurized gas discharged from the high-pressure-sidecompression chamber flows, wherein the discharge pipe is provided so asto penetrate the air guiding space so that the pressurized gas flowingthrough the discharge pipe is cooled by the cooling air introduced intothe air guiding space.

According to the configuration of (12), cooling of the pressurized gasdischarged from the high-pressure-side compression chamber can berealized using the air guiding space that forms the intermediate cooleras described above. The pressurized gas generated in the compressor bodyis discharged through a discharge pipe provided to penetrate the airguiding space. Therefore, the pressurized gas flowing through thedischarge pipe is cooled by the cooling air introduced into the airguiding space. By cooling the pressurized gas flowing through thedischarge pipe using the air guiding space that forms the intermediatecooler in this manner, an external device such as an after-cooler, forexample, is not necessary, and it is possible to reduce a system sizeand to effectively save an installation space and a manufacturing cost.

(13) In some embodiments, in the configuration of (12), a check valve isprovided in the discharge pipe.

In a scroll fluid machine, when the machine stops in the course ofoperation, a pressurized gas on a downstream side of a compressionchamber flows backward temporarily (instantaneously), and the revolvingscroll rotates in an opposite direction to generate noise. In order toprevent occurrence of such noise, a check valve for preventing backflowof a pressurized gas may be disposed on the downstream side of thecompression chamber. Since the usable temperature range of a check valveused for such use is limited due to a structure thereof, the check valvemay be unable to endure high-temperature gas immediately after beingdischarged from the compression chamber. However, according to theconfiguration of (13), since it is possible to decrease the temperatureof the pressurized gas flowing through the discharge pipe as describedabove, it is possible to arrange a backflow-prevention check valve inthe discharge pipe.

(14) In order to solve at least one of the problems, a scroll fluidmachine according to at least one embodiment of the present inventionincludes: a compressor body capable of generating a pressurized gas in acompression chamber formed by a fixed scroll and a revolving scroll; acover forming an air guiding space between the compressor body and thecover so that cooling air can be introduced into the air guiding space;and a discharge pipe connected to a discharge port formed in thecompressor body in order to discharge the pressurized gas generated inthe compression chamber and provided so as to penetrate the air guidingspace.

According to the configuration of (14), the pressurized gas generated inthe compressor body is discharged from the discharge port to the outsidethrough the discharge pipe. Since the discharge pipe is provided so asto penetrate the air guiding space to which the cooling air isintroduced, the high-temperature pressurized gas flowing through thedischarge pipe is cooled by the cooling air introduced into the airguiding space. The air guiding space is formed by the cover provided soas to cover the compressor body, and the temperature of the dischargedgas can be decreased effectively with a simple configuration.

(15) In some embodiments, in the configuration of (14), the dischargepipe is configured such that a heat exchanging portion exposed to theair guiding space has a higher heat conductivity than portionstherearound.

According to the configuration of (15), since the discharge pipe throughwhich a high-temperature pressurized gas flows has the heat exchangingportion which is exposed to the air guiding space and has a high heatconductivity, heat exchange with the cooling air introduced into the airguiding space is accelerated, and the temperature of the discharged gascan be decreased more effectively.

(16) In some embodiments, in the configuration of (14) or (15), coolingfins are formed on an outer surface of the discharge pipe.

According to the configuration of (16), by forming the cooling fins onthe outer surface of the discharge pipe, it is possible to increase aheat exchange area for heat exchange with the cooling air introducedinto the air guiding space and to decrease the temperature of thedischarged gas more effectively. Moreover, it is also possible toreinforce the mechanical strength of the discharge pipe through which ahigh-pressure pressurized gas flows.

(17) In some embodiments, in the configuration of (16), the cooling finextends in a flowing direction of the cooling air introduced into theair guiding space.

According to the configuration of (17), since the cooling fin formed onthe outer surface of the discharge pipe extends in the flowing directionof the cooling air, the cooling fin does not disturb the flow of thecooling air. As a result, heat exchange between the discharged gas andthe cooling air is accelerated, and the temperature of the dischargedgas can be decreased more effectively.

(18) In some embodiments, in the configuration of any one of (14) to(17), a check valve is provided in the discharge pipe.

According to the configuration of (18), since it is possible to decreasethe temperature of the pressurized gas flowing through the dischargepipe as described above, it is possible to arrange a backflow-preventioncheck valve in the discharge pipe. Due to this, it is not necessary toprovide a device such as an after-cooler outside the scroll compressor,and it is possible to decrease a device size and to save an installationspace and a manufacturing cost.

(19) In some embodiments, in the configuration of any one of (14) to(18), the compression chamber includes a low-pressure-side compressionchamber and a high-pressure-side compression chamber partitioned by apartition wall.

According to the configuration of (19), in a so-called single-windingtwo-stage scroll fluid machine in which the compression chamber ispartitioned into a low-pressure-side compression chamber and ahigh-pressure-side compression chamber by the partition wall, it ispossible to effectively cool the pressurized gas which is heated to ahigh temperature by being compressed in multiple stages.

(20) In order to solve at least one of the problems, a scroll fluidmachine according to at least one embodiment of the present inventionincludes: a fixed scroll having a fixed end plate and a fixed wrapformed on the fixed end plate; and a revolving scroll having a revolvingend plate and a revolving wrap formed on a first surface of the fixedend plate and forming a compression chamber together with the fixedscroll, wherein the revolving end plate has a convex shape in which asecond surface which is positioned on an opposite side of the firstsurface and to which cooling air is supplied swells continuously, andthe convex shape is formed so that a center of gravity of the revolvingscroll is identical to a center of revolution shifted from a center ofthe revolving end plate.

According to the configuration of (20), the second surface of therevolving end plate that forms the revolving scroll has a convex shape.Due to this, the thickness of the revolving end plate increases ascompared to a conventional scroll compressor, and the mechanicalstrength of the revolving scroll is improved. Moreover, since the convexshape of the second surface is formed so as to swell continuously, theconvex shape does not disturb the cooling air supplied to cool therevolving scroll. As a result, a satisfactory cooling effect is obtainedin the revolving scroll, and occurrence of distortion can be suppressedeffectively.

Conventionally, in order to adjust balance of a revolving scrollrotating eccentrically with respect to a driving shaft, a process ofadding a balance (padding) to the revolving scroll has been performed.However, such a countermeasure may make the device configuration complexand may increase a workload. According to the configuration of (20), byadjusting the convex shape formed on the revolving end plate, it ispossible to eliminate the need of the process of adding such a balance(padding). As a result, it is possible to adjust balance easily with asimple configuration.

(21) In some embodiments, in the configuration of (20), the convex shapeis formed in a region including the center of the revolving end plate.

According to the configuration of (21), since the convex shape is formedin such a wide region, the inclination of the convex shape becomesgentle. Due to this, the permeability of the cooling air on the secondsurface is improved, and a satisfactory cooling effect is obtained.

(22) In some embodiments, in the configuration of (20) or (21), aplurality of radiating fins extending in a blowing direction of thecooling air are formed on the second surface.

According to the configuration of (22), since the plurality of radiatingfins are formed on the second surface, the cooling performance of therevolving scroll can be improved further and the strength of therevolving scroll can be improved further. Moreover, in the revolvingscroll, since the convex shape is formed on the second surface of therevolving end plate, although the heat capacity increases as the volumeof the revolving end plate increases, it is possible to sufficientlycool the revolving scroll having a large heat capacity by forming suchradiating fins.

(23) In some embodiments, in the configuration of (22), the plurality ofradiating fins are arranged more densely as the thickness of therevolving end plate on the second surface increases.

According to the configuration of (23), the plurality of radiating finsformed on the second surface are arranged more densely in a region asthe thickness of the revolving end plate in the region increases. Due tothis, since a radiation amount corresponding to the heat capacity perunit area is obtained, it is possible to cool a wide region of therevolving scroll uniformly and to suppress distortion effectively.

(24) In some embodiments, in the configuration of any one of (20) to(23), the first surface has a concave reduced thickness portion on anon-contacting region that does not make contact with the fixed scroll.

According to the configuration of (24), although balance adjustment isperformed in a direction for increasing the weight of the revolving endplate by forming a convex shape on the second surface in the respectiveconfigurations described above, in the present embodiment, balanceadjustment of the revolving scroll can be performed in a direction fordecreasing the weight contrarily by forming the reduced thicknessportion. In this way, the balance of the revolving scroll can beadjusted more finely. Moreover, it is also possible to increase thevolume of the compression chamber considerably by forming the reducedthickness portion on the first surface.

(25) In some embodiments, in the configuration of at least one of (20)to (24), the compression chamber includes a low-pressure-sidecompression chamber and a high-pressure-side compression chamberpartitioned by a partition wall.

According to the configuration of (25), the scroll fluid machine isconfigured as a multi-stage fluid machine including thelow-pressure-side compression chamber and the high-pressure-sidecompression chamber partitioned by the partition wall as a compressionchamber. In such a multi-stage fluid machine, the temperature of thepressurized gas in the high-pressure-side compression chamber increasesparticularly. Therefore, by employing the above-described configuration,it is possible to secure strength in a wide range of regions whilesuppressing the increase in temperature of the revolving scrolleffectively and to realize a scroll fluid machine in which distortionrarely occurs.

(26) In order to solve at least one of the problems, a scroll fluidmachine according to at least one embodiment of the present inventionincludes: a fixed scroll having a fixed wrap formed on a fixed endplate; and a revolving scroll having a revolving wrap formed on arevolving end plate and forming a compression chamber together with thefixed scroll, wherein at least one of the fixed end plate and therevolving end plate includes a first surface having the fixed wrap orthe revolving wrap formed thereon, and a second surface positioned on anopposite side of the first surface and having a plurality of radiatingfins extending along cooling air introduced from a blower fan, and theplurality of radiating fins are arranged more densely on a downstreamside of the cooling air than on an upstream side.

According to the configuration of (26), the plurality of radiating finsare formed on a back surface (the second surface) on which the wrap ofthe fixed end plate or the revolving end plate is not formed. Sincethese radiating fins are arranged more densely on the downstream side ofthe cooling air than on the upstream side, the flow rate of the coolingair increases gradually from the upstream side toward the downstreamside. Therefore, the cooling effect on the downstream side where thetemperature of the cooling air increases is improved, and a temperaturedifference occurring between the downstream side and the upstream sidecan be suppressed. In this manner, it is possible to obtain a uniformcooling effect in a wide range of regions of the fixed scroll and therevolving scroll.

(27) In some embodiments, in the configuration of (26), the plurality ofradiating fins are arranged so that a pitch distance between adjacentradiating fins on the upstream side of the cooling air is larger thanthat on the downstream side.

According to the configuration of (27), by changing the pitch distancebetween the adjacent radiating fins, the plurality of cooling fins canbe arranged more densely on the downstream side of the cooling air thanon the upstream side.

(28) In some embodiments, in the configuration of (26) or (27), thecompression chamber is configured to be able to compress gas whilemoving toward the center when the fixed scroll and the revolving scrollare driven to rotate in relation to each other, and the plurality ofcooling fins are arranged more sparsely on a central side than an outercircumference side on at least one of the fixed end plate and therevolving end plate.

According to the configuration of (28), since the compression chamberformed by the fixed scroll and the revolving scroll compresses gastoward the central side, the temperature of the fixed scroll and therevolving scroll is likely to increase as it approaches the centralside. Therefore, by arranging the cooling fins more sparsely as itapproaches the central side where the temperature is high, coolingaccording to a thermal load distribution can be realized.

(29) In some embodiments, in the configuration of at least one of (26)to (28), the revolving end plate has a convex shape in which the secondsurface swells continuously, and the plurality of radiating fins arearranged more densely as the thickness of the revolving end plate on thesecond surface increases.

According to the configuration of (29), when the second surface of therevolving end plate forming the revolving scroll is formed so as to havea convex shape that swells continuously, by setting the density of theradiating fins according to the thickness of the revolving end plate, itis possible to obtain a uniform cooling effect over a wide range ofregions of the revolving end plate according to a heat capacitydistribution of the revolving end plate. In this way, it is possible toimprove the strength of the revolving scroll and to suppress occurrenceof distortion due to a temperature difference effectively.

(30) In some embodiments, in the configuration of at least one of (26)to (29), the fixed scroll and the revolving scroll are configured tothat the cooling air is introduced from the blower fan through a duct.

According to the configuration of (30), the cooling air supplied to thefixed scroll and the revolving scroll is introduced from the blower fanthrough a duct having a predetermined length. Therefore, although thecooling air is weakened considerably by a pressure loss occurring in theduct, since the present configuration has the plurality of cooling finsarranged as described above, a satisfactory cooling effect is obtainedwith a weak cooling air.

Advantageous Effects

According to at least one embodiment of the present invention, it ispossible to provide a scroll fluid machine capable of realizingsatisfactory compression efficiency with a simple configuration.

According to at least one embodiment of the present invention, it ispossible to provide a scroll fluid machine capable of decreasing amanufacturing cost and an installation space of entire facility, thescroll fluid machine including an intermediate cooler having a simpleconfiguration, disposed between a low-pressure-side compression chamberand a high-pressure-side compression chamber.

According to at least one embodiment of the present invention, it ispossible to provide a scroll fluid machine capable of effectivelydecreasing the temperature of discharged gas with a simpleconfiguration.

According to at least one embodiment of the present invention, it ispossible to provide a scroll fluid machine capable of improving thestrength in a wide range of regions while suppressing the increase intemperature of the revolving scroll effectively.

According to at least one embodiment of the present invention, it ispossible to provide a scroll fluid machine capable of obtaining auniform cooling effect over a wide range of regions of the fixed scrollor the revolving scroll.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating an appearance of a scrollcompressor according to at least one embodiment of the presentinvention.

FIG. 2 is a vertical cross-sectional view along a line passing through adriving shaft of the scroll compressor illustrated in FIG. 1.

FIG. 3 is a horizontal cross-sectional view along a line passing throughthe driving shaft of the scroll compressor illustrated in FIG. 1.

FIG. 4 is a plan view illustrating a revolving scroll provided in acompressor body illustrated in FIG. 1 when seen from a first surfaceside.

FIG. 5 is a plan view illustrating the revolving scroll illustrated inFIG. 4 when seen from a second surface side.

FIG. 6 is a comparative example of FIG. 5.

FIG. 7 is another modification of FIG. 5.

FIG. 8 is a plan view illustrating the fixed scroll included in thecompressor body illustrated in FIG. 1 when seen from a second surfaceside.

FIG. 9 is a cross-sectional view along a line passing through a centralaxis of the revolving scroll illustrated in FIG. 6.

FIG. 10 is a cross-sectional view along a line passing through thecentral axis of the revolving scroll illustrated in FIG. 4.

FIG. 11 is a contour distribution on the second surface of the revolvingscroll illustrated in FIG. 4.

FIG. 12 is a modification of FIG. 4.

FIG. 13 is a modification of FIG. 2.

FIG. 14 is another modification of FIG. 2.

FIG. 15 is a schematic diagram illustrating cooling fins provided on anouter surface of a discharge pipe illustrated in FIG. 14 when seen fromthe inner side of a cover.

FIG. 16 is a plan view illustrating a fixed scroll and a revolvingscroll of a single-winding two-stage scroll compressor.

FIG. 17 is a perspective view illustrating a state in which a cover isdetached from a scroll compressor according to the present embodiment.

FIG. 18 is a vertical cross-sectional view along a line passing througha driving shaft in a state in which a cover is attached to the scrollcompressor illustrated in FIG. 17.

FIG. 19 is a vertical cross-sectional view of a supercharging scrollcompressor.

DETAILED DESCRIPTION

Embodiments of the present invention will now be described in detailwith reference to the accompanying drawings. It is intended, however,that unless particularly specified, dimensions, materials, shapes,relative positions and the like of components described in theembodiments shall be interpreted as illustrative only and not limitativeof the scope of the present invention.

For example, an expression of relative or absolute arrangement such as“in a direction”, “along a direction”, “parallel”, “orthogonal”,“centered”, “concentric” and “coaxial” shall not be construed asindicating only the arrangement in a strict literal sense, but alsoincludes a state where the arrangement is relatively displaced by atolerance, or by an angle or a distance whereby it is possible toachieve the same function.

Furthermore, for example, an expression of a shape such as a rectangularshape or a cylindrical shape shall not be construed as only thegeometrically strict shape, but also includes a shape with unevenness orchamfered corners within the range in which the same effect can beachieved.

On the other hand, an expression such as “comprise”, “include”, “have”,“contain” and “constitute” are not intended to be exclusive of othercomponents.

<1. Entire Configuration>

FIG. 1 is a perspective view illustrating an appearance of a scrollcompressor 1 according to at least one embodiment of the presentinvention, FIG. 2 is a vertical cross-sectional view along a linepassing through a driving shaft 22 of the scroll compressor 1illustrated in FIG. 1, and FIG. 3 is a horizontal cross-sectional viewalong a line passing through the driving shaft 22 of the scrollcompressor 1 illustrated in FIG. 1. In the description below, the leftside of FIGS. 2 and 3 will be referred to as a front side and the rightside will be referred to as a rear side.

The scroll compressor 1 is a compressor for compressing gas such as airand includes a filter unit 2 for taking in and purifying a compressiontarget gas, a compressor body 4 for compressing the gas purified by thefilter unit 2, a power transmission unit 6 for transmitting dynamicpower from a dynamic power source (not illustrated) to respectiveportions of the scroll compressor 1, and a blower unit 8 for blowingcooling air of the scroll compressor 1. The filter unit 2 is disposed inan upper part on a front side of the scroll compressor 1, and thecompressor body 4, the power transmission unit 6, and the blower unit 8are disposed on a rear side of the filter unit 2 in that order from thefront side.

The filter unit 2 has a hollow filter casing 10 as a casing. Asillustrated in FIG. 2, the filter casing 10 includes a cylindricalportion 10 a having an approximately cylindrical shape and an inclinedportion 10 b disposed on a rear side of the cylindrical portion 10 a andinclined toward an outer surface of the compressor body 4. In thepresent embodiment, an intake port 12 for taking in a compression targetgas from the outside is formed in an upper surface of the inclinedportion 10 b of the filter casing 10. The intake port 12 is formed in aform of a plurality of slits extending in parallel in a left-rightdirection. It is not always necessary to form the intake port 12. Inthis case, the compression target gas is supplied from a blower fan 52(to be described later).

A filter element 14 for removing a foreign material such as dust or dirtincluded in the gas taken in from the intake port 12 is disposed in thefilter casing 10. The gas introduced from the intake port 12 isrectified by passing through the filter element 14 and is supplied tothe compressor body 4 positioned on the downstream side.

The compressor body 4 includes a compressor housing 16. The compressorhousing 16 is formed of an aluminum alloy, for example. An upper part onthe front side of the compressor housing 16 is connected to the filterunit 2, and the gas having passed through the filter element 14 isintroduced into the compressor body 4 through an introduction path 15.Moreover, the rear side of the compressor housing 16 is connected to abearing case 42 that forms the power transmission unit 6 by a pluralityof bolts (not illustrated).

A fixed scroll 18 which is an example of a first scroll and a revolvingscroll 20 which is an example of a second scroll are accommodated in thecompressor housing 16. The fixed scroll 18 is fixed to the compressorhousing 16, and the revolving scroll 20 is disposed in the compressorhousing 16 so as to face the fixed scroll 18. The revolving scroll 20 issupported by an eccentric shaft portion 23 provided at a distal end ofthe driving shaft 22 and is rotated by dynamic power transmitted fromthe power transmission unit 6.

The fixed scroll 18 includes a fixed end plate 19 having anapproximately disk shape. A fixed wrap 21 having a spiral shape isformed on a first surface of the fixed end plate 19 facing the revolvingscroll 20. Radiating fins 24 for heat radiation are formed on a secondsurface of the fixed end plate 19 on the opposite side of the firstsurface. As will be described later, cooling air delivered from theblower unit 8 is supplied to the radiating fins 24 to cool the fixedscroll 18.

The revolving scroll 20 includes a revolving end plate 26 having anapproximately disk shape. A revolving wrap 28 having a spiral shape iserected on a first surface of the revolving end plate 26 facing thefixed scroll 18. Radiating fins 30 for heat radiation are formed on asecond surface of the revolving end plate 26 on the opposite side of thefirst surface. As will be described later, cooling air supplied from theblower unit 8 is introduced to the radiating fins 30 to cool the fixedscroll 18.

In respective embodiments including the present embodiment, the lengthof the fixed wrap 21 of the fixed scroll 18 and the length of therevolving wrap 28 of the revolving scroll 20 are different. That is, thescroll compressor 1 according to the respective embodiments is aso-called asymmetric wrap scroll compressor. However, the presentapplication invention is not limited to the asymmetric wrap scrollcompressor but may be a so-called symmetric wrap scroll compressor inwhich the length of the fixed wrap 21 and the length of the revolvingwrap 28 are the same.

A revolving plate 32 having an approximately disk shape is fixed to therear side of the revolving scroll 20 in a state of being directlyconnected to the eccentric shaft portion 23 of the driving shaft 22. Abearing portion 37 is formed integrally with the revolving plate 32. Arotating bearing 33 for rotatably supporting the eccentric shaft portion23 provided at the distal end of the driving shaft 22 is disposed in thebearing portion 37. A plurality of rotation prevention mechanisms 34 forallowing the revolving scroll 20 to revolve while preventing rotation ofthe revolving scroll 20 are provided between the revolving plate 32 andthe compressor housing 16 at approximately equal intervals in acircumferential direction of the revolving plate 32 (that is, therevolving scroll 20).

When the driving shaft 22 is rotated with the dynamic force from thepower transmission unit 6, the revolving scroll 20 performs revolvingmotion whereby the volume of the compression chamber 36 formed betweenthe fixed scroll 18 and the revolving scroll 20 decreases gradually fromthe outer circumference side toward the inner circumference side andintake and compression cycles are performed. More specifically, such acompression chamber 36 is formed in an approximately crescent shape bybeing partitioned by the fixed wrap 21 and the revolving wrap 28. Inthis way, the gas introduced from the introduction path 15 into thecompressor body 4 is compressed gradually as it approaches the innercircumference side. The pressurized gas generated in the compressionchamber 36 is discharged from a discharge port 38 formed in a centralportion of the fixed scroll 18.

Here, a lid portion 53 having a flat plate shape is fixed to the frontside of the compressor housing 16. The lid portion 53 is covered by acover 63 from a more front side, and an air guiding space 57 to which aportion of the cooling air from the blower unit 8 can be introduced isformed between the lid portion 53 and the cover 63.

A discharge plug 67 connected to a pressurized gas supply destinationpresent at the outside is provided on an outer surface of the cover 63.The discharge plug 67 is connected to the discharge port 38 formed inthe central portion of the fixed scroll 18 through a discharge pipe 59arranged on the inner side of the cover 63 so as to penetrate the airguiding space 57. In this way, the pressurized gas generated in thecompression chamber 36 is discharged from the discharge port 38 to theoutside through the discharge pipe 59.

The power transmission unit 6 is a unit having a function oftransmitting dynamic power supplied from a dynamic power source (notillustrated) to respective portions of the scroll compressor 1. In thepresent embodiment, the power transmission unit 6 has a driven pulley 40which is disposed at a rear end of a driving shaft 22 protruding towarda rear side of the blower unit 8 and to which the dynamic power from anexternal dynamic power source can be input. An upper part of an endlesspower transmission belt (not illustrated) of which the lower part isstretched around a main pulley (not illustrated) attached to an outputshaft of a dynamic power source such as a motor or an engine provided onthe lower side of the scroll compressor 1, for example, is stretchedaround the driven pulley 40, whereby rotation of the dynamic powersource is transmitted to the driving shaft 22. The dynamic power inputto the driven pulley 40 rotates the driving shaft 22 and is transmittedto the respective portions of the scroll compressor 1 such as thecompressor body 4 and the blower unit 8.

The bearing case 42 that forms a casing of the power transmission unit 6is formed of a casting, for example, having a higher strength than thecompressor housing 16. Ball bearings 44 and 46 provided so as to beseparated by a predetermined distance in a front-rear direction aredisposed in the bearing case 42 and the driving shaft 22 is rotatablysupported.

The eccentric shaft portion 23 is provided on a front end side of thedriving shaft 22. Moreover, as illustrated in FIG. 2, a balance weight48 for adjusting balance of the revolving scroll 20 is provided on anouter circumference of a front part of the eccentric shaft portion 23.

The blower unit 8 accommodates a blower fan 52 in the fan casing 50. Theblower fan 52 is connected to the driving shaft 22 and is configured tobe rotatable with the dynamic power transmitted from the powertransmission unit 6. The blower fan 52 is a sirocco fan, for example.

When the blower fan 52 is driven, the blower unit 8 takes in the outsideair (air) from an opening 55 formed on a front side of the fan casing50, and the outside air is transferred toward the duct 54 formed on thedownstream side of the blower fan 52. The duct 54 is a tubular memberhaving an approximately cylindrical shape, and as illustrated in FIG. 3,is configured to circumvent a lateral side of the power transmissionunit 6 from a lateral side of the fan casing 50 to be connected to thecompressor body 4 from a lateral side. In this way, the outside airdelivered from the blower unit 8 to the duct 54 is supplied to thecompressor body 4 as cooling air.

As illustrated in FIG. 3, the cooling air introduced from the duct 54into the compressor body 4 is distributed to a first air passage 56, asecond air passage 58, and a third air passage 60 inside the compressorhousing 16. The first air passage 56 is a passage for supplying thecooling air to the radiating fins 30 formed on the second surface of therevolving end plate 26 and mainly cools the revolving scroll 20. Thesecond air passage 58 is a passage for supplying the cooling air to theradiating fins 24 formed on the second surface of the fixed end plate 19and mainly cools the fixed scroll 18. The third air passage 60 is apassage for supplying the cooling air to the air guiding space 57 formedon the front side of the compressor housing 16.

<2. Configuration of Radiating Fins in Fixed Scroll and RevolvingScroll>

Next, the configuration of the radiating fins 24 and 30 provided in thefixed scroll 18 and the revolving scroll 20, respectively, in the scrollcompressor 1 according to the present embodiment will be described indetail. In this section, although the radiating fins 30 formed on therevolving scroll 20 will be mainly described, the radiating fins 24formed on the fixed scroll 18 have a similar configuration unlessparticularly stated otherwise.

FIG. 4 is a plan view illustrating the revolving scroll 20 included inthe compressor body 4 illustrated in FIG. 1 when seen from the firstsurface, and FIG. 5 is a plan view illustrating the revolving scroll 20illustrated in FIG. 4 when seen from the second surface. As illustratedin FIG. 4, a spiral revolving wrap 28 is erected on the revolving endplate 26 on the first surface of the revolving scroll 20. A grooveportion 61 with which a tip seal (not illustrated) for sealing a gapbetween the fixed scroll 18 and the revolving wrap 28 can engage isformed at a distal end of the revolving wrap 28 along the lengthdirection of the revolving wrap 28.

Moreover, as illustrated in FIG. 5, a plurality of radiating fins 30 areerected on the revolving end plate 26 on the second surface of therevolving scroll 20. The cooling air from the duct 54 is introduced tothe plurality of radiating fins 30 through the first air passage 56 (seeFIG. 3). The plurality of radiating fins 30 formed on the revolving endplate 26 have an approximately straight shape and extend approximatelyin parallel in the flowing direction of the cooling air introduced fromthe first air passage 56.

Here, FIG. 6 is a comparative example of FIG. 5. As illustrated in FIG.6, in a conventional scroll compressor, a plurality of radiating fins30′ formed on a revolving end plate 26′ have a non-straight shape (awave form) curved in a wave form. In the radiating fin 30′ having such anon-straight shape, turbulence may be generated along the line curved ina wave form and a flow resistance may increase. In contrast, in thepresent embodiment, by using the radiating fins 30 having anapproximately straight shape as in FIG. 5, since the heat exchange ratewith the radiating fins 30 can be improved without disturbing the flowof the cooling air from the first air passage 56, it is possible toobtain a satisfactory cooling performance.

Moreover, since the cooling air introduced to the radiating fins 30 issupplied from the blower fan 52 at a distant position through the duct54 having a predetermined length, the cooling air is introduced to theradiating fins 30 in a state in which the wind power is weakenedconsiderably by a pressure loss. However, in the present embodiment, asdescribed above, since the radiating fins 30 have an approximatelystraight shape, the cooling air of which the wind power is weakened inthis manner can realize satisfactory heat exchange and provide anexcellent cooling effect. For example, in this type of scroll compressor1, although an electric motor is often integrated with the powertransmission unit 6 as a dynamic power source, in this case, the size ofthe power transmission unit 6 may increase and hence, the length of theduct 54 also increases. When the length of the duct 54 increases in thismanner, although the cooling air passing through the duct 54 is likelyto be influenced from a pressure loss, a satisfactory cooling effect canbe secured due to the above-mentioned effect.

Moreover, as illustrated in FIG. 6, a plurality of conventionalradiating fins 30′ are typically provided at approximately equalintervals in the blowing direction of the cooling air. Therefore,although the cooling air introduced from the first air passage 56 canobtain a relatively satisfactory cooling effect on the upstream side ofthe radiating fins 30′, the temperature of the cooling air may increasegradually on the downstream side and the cooling effect may deteriorate.As a result, due to such a bias in the cooling effect, a temperaturedifference may occur on the revolving scroll 20, which may cause adistortion.

In contrast, in the present embodiment, as illustrated in FIG. 5, theplurality of radiating fins 30 are arranged more densely on thedownstream side of the cooling air than on the upstream side. In theexample of FIG. 5, particularly, the plurality of radiating fins 30 areconfigured so that a pitch distance between the adjacent radiating fins30 is larger on the upstream side of the cooling air than on thedownstream side. More specifically, a pitch distance L1 on the upstreamside is larger than a pitch distance L2 on the downstream side.Therefore, the flow rate of the cooling air introduced from the firstair passage 56 increases as it approaches the downstream side (that is,the flow rate V2 on the downstream side is larger than the flow rate V1on the upstream side), and a bias in the cooling effect between theupstream side and the light sources can be alleviated. As a result, itis possible to cool the revolving scroll 20 uniformly and to effectivelysuppress occurrence of distortion in the revolving scroll 20.

The plurality of radiating fins 30 may be configured to be more denselyon the downstream side of the cooling air than on the upstream side byforming the same to be thicker on the downstream side than on theupstream side of the cooling air. In this case, similarly to FIG. 5,since the gap between the radiating fins 30 narrows as it approaches thedownstream side, the flow rate of the cooling air increases as itapproaches the downstream side, and advantages similar to thosedescribed above can be obtained.

FIG. 7 is another modification of FIG. 5. As illustrated in FIG. 7, theplurality of radiating fins 30 may be arranged to be more sparsely onthe central side than on the outer circumference side of the revolvingscroll 20. As described above, since the temperature of the pressurizedgas in the compression chamber 36 increases as it approaches the centralportion of the compression chamber 36, by arranging the radiating fins30 so as to be more sparsely as it approaches the inner side, it ispossible to confine a larger amount of cooling air on the inner side(that is, the central side). Therefore, a higher cooling effect isobtained as it approaches the inner side where the temperature is likelyto increase. In this way, it is possible to perform cooling according toa thermal load distribution of the revolving scroll 20 and to suppressoccurrence of distortion in the revolving scroll 20 more effectively.

Although the radiating fins 30 of the revolving scroll 20 have beendescribed, the same idea can be applied to the radiating fins 24 of thefixed scroll 18. For example, when an example of the radiating fins 24of the fixed scroll 18 is described representatively by referring toFIG. 8, since the cooling air is introduced to the radiating fins 24 ofthe fixed scroll 18 through the second air passage 58, the radiatingfins 24 having an approximately straight shape and extendingapproximately in parallel along the cooling air are arranged on thesecond surface of the fixed scroll 18. These radiating fins 24 arearranged so as to be more densely on the downstream side of the coolingair supplied from the second air passage 58 than on the upstream sideand to be more sparsely on the outer circumference side than on thecentral side, and modifications similar to those of the radiating fins30 of the revolving scroll 20 can be applied.

<3. Reinforcement Structure of Revolving Scroll>

Next, a reinforcement structure of the revolving scroll 20 in the scrollcompressor 1 according to the present embodiment will be described indetail. In this type of scroll compressor 1, since the revolving scroll20 is rotated by the torque of the driving shaft 22, distortion is morelikely to occur in the revolving scroll 20 than in the fixed scroll 18fixed to the compressor housing 16. Therefore, in the presentembodiment, by employing a reinforcement structure to be described laterin the revolving scroll 20, it is possible to improve mechanicalstrength and suppress distortion of the revolving scroll 20.

Here, a reinforcement structure according to a comparative example willbe described as a premise according to the present embodiment. FIG. 9 isa cross-sectional view along a line passing through a central axis ofthe revolving scroll 20′ illustrated in FIG. 6 (comparative example). Inthe revolving scroll 20′ of the comparative example, a reinforcement rib70 is formed on the revolving end plate 26 having a uniform thickness.The reinforcement rib 70 is formed so as to pass through the centralportion of the revolving end plate 26 on the second surface on which theradiating fins 30 are formed and to extend in a direction approximatelyvertical to the radiating fins 30.

However, although such a linear reinforcement rib 70 provides arelatively effective reinforcement effect in the vicinity of thereinforcement rib 70, it is difficult to obtain a sufficientreinforcement effect in a region distant from the reinforcement rib 70,and it is not possible to sufficiently reinforce the entire revolvingscroll 20. Moreover, as illustrated in FIG. 9, since the reinforcementrib 70 has a shape that protrudes in a convex shape from the secondsurface, the cooling air from the first air passage 56 may collide froma lateral surface of the reinforcement rib 70 to disturb the flow of thecooling air and may deteriorate the cooling performance of the revolvingscroll 20.

In the present embodiment, the revolving end plate 26 has a convex shape80 in which the second surface swells continuously. FIG. 10 is across-sectional view along a line passing through the central axis ofthe revolving scroll 20 illustrated in FIG. 4, and FIG. 11 is a contourdistribution of the revolving end plate 26 on the second surface of therevolving scroll 20. The revolving end plate 26 has a non-uniformthickness so that the height increases about an apex 81 as a center andhas a gentle mountain-shaped cross-sectional shape. Due to this, ascompared to the revolving end plate 26 having a uniform thickness as inthe conventional revolving scroll (see FIG. 9), the thickness of therevolving scroll 20 increases and the strength is improved. Moreover,since such a convex shape 80 is formed continuously (smoothly), it ispossible to realize satisfactory heat exchange with the radiating fins30 without disturbing the flow of the cooling air from the first airpassage 56. In this manner, it is possible to reinforce the revolvingscroll 20 with a compact configuration while securing a coolingperformance.

As illustrated in FIG. 11, the convex shape 80 on the revolving endplate 26 is formed so that a center of gravity 82 of the revolvingscroll 20 is identical to the center of revolution shifted from thecenter O of the revolving end plate 26. More specifically, in theexample of FIG. 11, the apex 81 of the convex shape 80 is shifted to atop-left corner from the center O of the revolving end plate 26, and asa result, the center of gravity 82 is also shifted from the center O.Generally, since the revolving scroll 20 is rotated in an eccentricstate, although a process of adding a balance (padding) to the revolvingscroll 20 has conventionally been performed in order to adjust thebalance of the revolving scroll 20 finely, this process may make thedevice configuration complex and may increase a workload. In thisrespect, in this configuration, since the position of the center ofgravity 82 of the revolving scroll 20 can be adjusted arbitrarily byforming the convex shape 80 on the second surface, such a problem can besolved with a simple configuration.

Moreover, the convex shape 80 on the second surface of the revolving endplate 26 may be formed over a region including the center O. When theconvex shape 80 is formed in such a wide region, the inclination of theconvex shape 80 becomes gentle. As a result, the cooling air passes moreeasily and a satisfactory cooling performance can be achieved.

As described above, the plurality of radiating fins 30 extending in theblowing direction of the cooling air are formed on the second surfacehaving such a convex shape 80. As described above, in the revolvingscroll 20, since the thickness of the revolving end plate 26 increasesdue to the convex shape 80 formed on the second surface of the revolvingend plate 26, although the heat capacity also increases, it is possibleto effectively cool the revolving scroll 20 having a large heat capacityby forming such radiating fins 30. Moreover, by forming the radiatingfins 30, it is possible to further improve the strength of the revolvingscroll 20.

The plurality of radiating fins 30 are arranged on the second surface asdescribed with reference to FIGS. 5, 6, and 7. However, as anotherembodiment, the plurality of radiating fins 30 may be arranged so as tobe more densely as the thickness of the revolving end plate 26 on thesecond surface increases. That is, the arrangement density of theradiating fins 30 in a region which increases as the thickness of therevolving end plate 26 having the convex shape 80 in the regionincreases. Due to this, since a radiation amount can be distributedaccording to the heat capacity per unit area, it is possible to cool awide region of the revolving scroll 20 uniformly and to suppressdistortion of the revolving scroll 20 more effectively.

Moreover, the first surface of the revolving scroll 20 may have aconcave reduced thickness portion 92 in at least a portion of anon-contacting region 90 that does not make contact with the fixedscroll 18. FIG. 12 is a modification of FIG. 4. The first surface of therevolving scroll 20 is disposed so as to face the fixed scroll 18 andforms the compression chamber 36 together with the fixed scroll 18.Here, the non-contacting region 90 that does not make contact with thefixed scroll 18 when the revolving scroll 20 revolves by being driven bythe driving shaft 22 is present as illustrated in FIG. 12. Thenon-contacting region 90 is a region of the first surface of therevolving end plate 26 of the revolving scroll 20, located closer to theouter circumference side than at least the revolving wrap 28 at theoutermost circumference (a portion of the revolving wrap 28corresponding to one winding from the outermost circumferential end).

Although FIG. 12 illustrates a case in which the entire non-contactingregion 90 is formed as a concave reduced thickness portion 92, a portionof the non-contacting region 90 may be formed as a partially concavereduced thickness portion 92.

In the respective embodiments, the balance is adjusted in the directionfor increasing the weight of the revolving end plate 26 by forming theconvex shape 80 on the second surface of the revolving scroll 20.However, in this configuration, the balance of the revolving scroll 20can be adjusted in the direction for decreasing the weight contrarily byforming the reduced thickness portion 92. In this way, the balance ofthe revolving scroll 20 can be adjusted more finely. Moreover, thevolume of the compression chamber 36 can be extended by forming thereduced thickness portion 92 on the first surface.

Although it has been described that the reduced thickness portion 92 maybe formed on the first surface of the revolving scroll 20, the reducedthickness portion 92 may be formed on the first surface of the fixedscroll 18. In this case, since the fixed scroll 18 is fixed to thecompressor housing 16, although a balance adjustment effect is notobtained, it is possible to decrease the weight of the fixed scroll 18by forming the reduced thickness portion 92 and to contribute toincreasing the volume of the compression chamber 36.

<4. Cooling Structure of Pressurized Gas>

Next, a cooling structure of the pressurized gas discharged from thecompressor body 4 will be described. As illustrated in FIG. 2, the airguiding space 57 to which the cooling air can be introduced through thethird air passage 60 is formed between the cover 63 and the fixed scroll19 (the lid portion 53) of the compressor body 4. A discharge pipe 59through which the pressurized gas discharged from the discharge port 38of the compressor body 4 flows is disposed so as to penetrate the airguiding space 57 toward the outside.

The discharge pipe 59 is configured so as to make contact with thecooling air flowing through the air guiding space 57 from the outside,and the high-temperature pressurized gas flowing through the dischargepipe 59 is cooled by heat exchange with the cooling air introduced intothe air guiding space 57. Conventionally, the high-temperaturepressurized gas discharged from the compressor body 4 is supplied to adesired destination after being cooled by an after-cooler provided atthe outside. However, in the present embodiment, since the pressurizedgas can be cooled in the air guiding space 57 in this manner, anexternal device such as an after-cooler is not necessary, and it isadvantageous in decreasing the size of the entire system.

Here, a heat exchanging portion 59 a of the discharge pipe 59 exposed tothe air guiding space 57 may be configured such that a heat conductivitythereof is higher than portions therearound. For example, the heatexchanging portion 59 a may be partially formed of a material (forexample, aluminum) having a high heat conductivity and may have apartially small thickness. In this manner, since the discharge pipe 59through which the high-temperature pressurized gas from the compressorbody 4 flows has the heat exchanging portion 59 a having a high heatconductivity, exposed to the air guiding space 57, it is possible toaccelerate heat exchange with the cooling air introduced into the airguiding space 57 and to cool the discharged gas more effectively.

FIG. 13 is a modification of FIG. 2. In this modification, the dischargepipe 59 has an enlarged diameter portion 97 having an enlarged diameter,and a check valve 98 for preventing backflow of the discharged gas isincluded in the enlarged diameter portion 97. In this type of scrollcompressor 1, when a compression cycle stops, a phenomenon that thepressurized gas remaining in the discharge pipe 59 temporarily flowsback toward the compressor body 4 may occur. Although a configuration inwhich a check valve is provided on the downstream side of the dischargeport 38 has conventionally been used in order to suppress occurrence ofsuch a backflow phenomenon, this type of check valve has a limited rangeof use temperature and cannot endure the high-temperature pressurizedgas discharged from the discharge port 38. Therefore, it is necessary tocool the high-temperature pressurized gas using an after-cooler providedon the downstream side as described above and to arrange a check valveon the downstream side thereof, which may increase the size of a system.In this respect, in the present embodiment, since the pressurized gas ofthe discharge pipe 59 is cooled by the air guiding space 57, the checkvalve 98 can be included in the enlarged diameter portion 97 provided inthe discharge pipe 59. In this way, it is possible to decrease the sizeof the entire system effectively.

FIG. 14 is another modification of FIG. 2, and FIG. 15 is a schematicdiagram illustrating the cooling fins 95 formed on the outer surface ofthe discharge pipe 59 illustrated in FIG. 14 when seen from the innerside of the cover 63. In this modification, the cooling fins 95 areformed on the outer surface of the discharge pipe 59. By forming suchcooling fins 95, it is possible to increase a heat exchange area forheat exchange with the cooling air introduced into the air guiding space57 and to decrease the temperature of the discharged gas moreeffectively. Moreover, such cooling fins 95 are effective in reinforcingthe mechanical strength of the discharge pipe 59 through which thehigh-pressure pressurized gas flows. Particularly, when the thickness ofthe discharge pipe 59 is partially decreased as described above,although the strength of the discharge pipe 59 itself decreases, thestrength can be reinforced by forming such cooling fins 95.

Moreover, in this modification, the cooling fins 95 extend in theflowing direction (the left-right direction) of the cooling airintroduced into the air guiding space 57 through the third air passage60 and are configured so as not to disturb the flow of the cooling air.As a result, it is possible to accelerate heat exchange between thedischarged gas and the cooling air and to decrease the temperature ofthe discharged gas more effectively.

<5. Intermediate Cooler>

In the above-described embodiments, although the scroll compressor 1that compresses gas in a single stage has been described, the scrollcompressor 1 may be configured as a multi-stage compressor thatcompresses gas in multiple stages. In the following embodiment, a casein which the scroll compressor 1 is configured as a single-windingtwo-stage scroll compressor will be described.

FIG. 16 is a plan view illustrating the fixed scroll 18 and therevolving scroll 20 of a single-winding two-stage scroll compressor 1.In this scroll compressor 1, a partition wall 102 for partitioning alow-pressure-side compression chamber 36 a and a high-pressure-sidecompression chamber 36 b is formed in a spiral groove formed by a fixedwrap 21 formed on the fixed end plate 19 of the fixed scroll 18. Thatis, the partition wall 102 is formed in a boss shape on the fixed endplate 19 so that the spiral groove formed by the fixed wrap 21 isblocked halfway. When the passage of the pressurized gas of thecompression chamber 36 is blocked by such a partition wall 102, thecompression chamber 36 is partitioned into the low-pressure-sidecompression chamber 36 a and the high-pressure-side compression chamber36 b.

The partition wall 102 may be formed integrally with the fixed end plate19 and may be formed as a separate member.

A low-pressure-side discharge port 104 and a high-pressure-side inletport 106 are formed on both sides (that is, the inner side of thelow-pressure-side compression chamber 36 a and the outer side of thehigh-pressure-side compression chamber 36 b) of the partition wall 102of the spiral groove 100. The low-pressure-side discharge port 104 andthe high-pressure-side inlet port 106 are formed so as to penetrate thefixed end plate 19 approximately in parallel to the central axis line ofthe fixed scroll 18. The low-pressure-side compression chamber 36 a ispositioned on the outer side as compared to the high-pressure-sidecompression chamber 36 b and a compression target gas (outside air) isintroduced therein from the introduction path 15. The pressurized gaspressurized in the low-pressure-side compression chamber 36 a isdischarged from the low-pressure-side discharge port 104 and is cooledby an intermediate cooler 110 to be described later and is thenintroduced into the high-pressure-side inlet port 106 of thehigh-pressure-side compression chamber 36 b. In the high-pressure-sidecompression chamber 36 b, the pressurized gas cooled by the intermediatecooler 110 is further compressed, and the pressurized gas is finallydischarged from the discharge port 38 formed on a central side of thefixed end plate 19.

Here, FIG. 17 is a perspective view illustrating a state in which thecover 63 is detached from the scroll compressor 1 according to thepresent embodiment, and FIG. 18 is a vertical cross-sectional view alonga line passing through the driving shaft 22 in a state in which thecover 63 is attached to the scroll compressor 1 illustrated in FIG. 17.

The scroll compressor 1 includes the intermediate cooler 110 configuredto cool the pressurized gas discharged from the low-pressure-sidecompression chamber 36 a and to return the cooled pressurized gas to thehigh-pressure-side compression chamber 36 b. The intermediate cooler 110is an air-cooled cooler and includes the air guiding space 57 to whichcooling air is introduced and a radiating pipe 112 which is disposedinside the air guiding space 57 and through which the pressurized gasdischarged from the low-pressure-side compression chamber 36 a flows.

As described above, the air guiding space 57 is formed by the lidportion 53 fixed to the fixed scroll and the cover 63 covering the lidportion 53, and the cooling air is introduced into the air guiding space57 through the third air passage 60. Moreover, the radiating pipe 112connecting the low-pressure-side discharge port 104 of thelow-pressure-side compression chamber 36 a and the high-pressure-sideinlet port 106 of the high-pressure-side compression chamber 36 b isdisposed on the lid portion 53 within the inner wall of the air guidingspace 57. The radiating pipe 112 is exposed to the cooling airintroduced from the third air passage 60 through an opening 100 formedin the vicinity of an edge of the lid portion 53 of the air guidingspace 57 whereby the high-temperature pressurized gas flowing throughthe radiating pipe 112 is cooled. In this manner, the intermediatecooler 110 for cooling the pressurized gas using the cooling airintroduced into the air guiding space 57 can be formed to be integratedwith the compressor body 4. Such a configuration is simpler than theconventional configuration, and it is possible to reduce a manufacturingcost and an installation space of entire facility effectively.

The radiating pipe 112 is formed of a metal material having an excellentheat conductivity such as aluminum, for example. Moreover, the radiatingpipe 112 is formed in a convex shape on the lid portion 53 and isconfigured so that a contact area contacting the cooling air introducedinto the air guiding space 57 increases.

Moreover, as illustrated in FIG. 17, the radiating pipe 112 is arrangedon the lid portion 53 so as to be folded back in a predeterminedpattern. Since the radiating pipe 112 has such a folded-back shape, itis possible to secure a large contact area with the cooling airintroduced into the air guiding space 57 and to obtain a satisfactorycooling effect.

When the configuration of the radiating pipe 112 is described in furtherdetail, the radiating pipe 112 has a shape in which a plurality ofradiating portions 113 extending along the cooling air introduced fromthe third air passage 60 are connected by a plurality of folded-backportions 114 formed to be lower than the plurality of radiating portions113. Since the radiating pipe 112 has such a folded-back shape, it ispossible to arrange the long radiating pipe 112 in a limited compactspace on the lid portion 53. Moreover, since the plurality of radiatingportions 113 extends in the blowing direction, the radiating portions donot disturb the flow of the cooling air. Furthermore, since thefolded-back portions 114 are formed to be lower than the radiatingportions 113, the outside air is introduced smoothly between theadjacent radiating portions 113. In this manner, a satisfactory coolingeffect is obtained with the radiating pipe 112.

In the present embodiment, the low-pressure-side discharge port 104 isdisposed on the downstream side of the cooling air as compared to thehigh-pressure-side inlet port 106 on the lid portion 53 that forms theinner wall of the air guiding space 57. Moreover, as illustrated in FIG.17 in which the passage of the pressurized gas in the radiating pipe 112is indicated by a broken line, the radiating pipe 112 is configured topass more closely through the downstream side than the central portionof the lid portion 53 and to be connected to the high-pressure-sideinlet port 106 while circumventing the upstream side so as to surroundthe central portion. Due to this, the pressurized gas flowing throughthe radiating pipe 112 flows from the downstream side toward theupstream side as indicated by arrows in FIG. 17. As a result, thetemperature of the pressurized gas flowing through the radiating pipe112 on the upstream side of the cooling air decreases as compared to onthe downstream side. Therefore, the cooling air on the upstream sideexchanges heat with a relatively low-temperature pressurized gas and thecooling air having a low temperature can be supplied to the radiatingpipe 112 on the downstream side, through which a relativelyhigh-temperature pressurized gas flows. In this way, a satisfactorycooling effect is obtained in the entire radiating pipe 112.

The air guiding space 57 that forms the intermediate cooler 110 may beused for cooling the pressurized gas passing through the discharge pipe59 similarly to the above-described embodiments. In this case, since thepressurized gas discharged from the discharge pipe 59 is cooled usingthe air guiding space 57 that forms the intermediate cooler 110, anexternal device such as an after-cooler, for example, is not necessary,and it is possible to reduce a system size and to effectively save aninstallation space and a manufacturing cost.

Moreover, as illustrated in FIGS. 14 and 15, when the radiating fins 97are formed on the outer surface of the discharge pipe 59, thepermeability of the cooling air introduced from the third air passage 60may be improved by arranging the radiating fins 97 in an arrangementpattern corresponding to an arrangement pattern of the radiating pipes112 of the intermediate cooler 110.

The radiating pipe 112 may be arranged more densely on the downstreamside of the cooling air introduced through the third air passage 60 thanon the upstream side similarly to the radiating fins 30 described withreference to FIG. 5. In this way, since the passage area decreases fromthe upstream side toward the downstream side, the flow rate of thecooling air introduced to the radiating pipes 112 increases as itapproaches the downstream side where the temperature of the cooling airincreases. As a result, a uniform cooling effect is obtained in theentire radiating pipe 112.

<6. Supercharge Structure of Cooling Air>

Although the above-described embodiment employs a natural intake scrollcompressor in which gas compressed by the compressor body 4 isintroduced directly from an intake port of the filter unit 2, asupercharging scroll compressor may be employed as in the embodiment tobe described later. FIG. 19 is a vertical cross-sectional view of asupercharging scroll compressor 11.

FIG. 19 is a modification of FIG. 2, the corresponding elements will bedenoted by the same reference numerals, and redundant description willbe omitted appropriately.

In the embodiment of FIG. 19, a compression target gas is taken in froman opening 55 of the blower unit 8. That is, in the present embodiment,a portion of the outside air taken in from the blower unit 8 is used asthe compression target gas, and the remaining is used as the cooling airof the compressor body 4. In the present embodiment, the intake port 12of the filter unit 2 illustrated in FIG. 2 is sealed.

In the scroll compressor 1, when the blower fan 52 is driven by thedriving shaft 22, outside air is taken in from the opening 55 of theblower unit 8. The outside air taken in from the opening 55 is deliveredto the compressor body 4 through the duct 54 connected to a lateral sideof the blower unit 8. The duct 54 is connected to the lateral side ofthe compressor body 4, and similarly to the above-described embodiment,branches into the first air passage 56, the second air passage 58, andthe third air passage 60. The outside air introduced into the first airpassage 56 and the second air passage 58 is supplied to the radiatingfins 24 and 30 formed on the back surface of the fixed scroll 18 and therevolving scroll 20, respectively, to thereby cool the fixed scroll 18and the revolving scroll 20, respectively.

On the other hand, the outside air introduced into the third air passage60 is supercharged into the introduction path 15 of the compressor body4. Here, the air guiding space 57 formed by the lid portion 53 and thecover 63 communicates with the filter casing 10 of the filter unit 2disposed on the upper side thereof (that is, an opening 120 is formed inthe lower part of the filter casing 10 so as to communicate with the airguiding space 57). Therefore, the outside air supplied from the thirdair passage 60 is delivered to the filter unit 2 through the air guidingspace 57. In the filter unit 2, the outside air delivered from the airguiding space 57 passes through the filter element 14 whereby a foreignmaterial is removed therefrom, and after that, the outside air issupercharged into the compressor body 4.

In this manner, a portion of the cooling air supplied from the blowerfan 52 in order to cool the fixed scroll 18 and the revolving scroll 20is configured to be supercharged into the compressor body 4. That is,since a portion of the cooling air used as air for cooling the fixedscroll 18 and the revolving scroll 20 can be supercharged, in spite of asimple configuration, it is possible to realize the scroll compressor 1capable of obtaining satisfactory compression efficiency whilesuppressing the increase in temperature of the fixed scroll 18 and therevolving scroll 20.

Here, the cooling air supercharged into the compressor body 4 issupercharged through the air guiding space 57. Since the cooling airpasses through the air guiding space 57, dynamic pressure of the coolingair from the duct 54 is converted to static pressure and the cooling airhaving the static pressure is supercharged into the compressor body 4.Therefore, even if a variation such as pulsation is present in the gassupplied from the duct 54, stable supercharging can be realized.Particularly, since the air guiding space 57 has a larger passage areathan the duct 54, it is possible to convert the dynamic pressure of thecooling air delivered from the duct 54 to static pressuresatisfactorily, and stable supercharging can be realized.

Moreover, the cover 63 that forms the air guiding space 57 has a curvedinner wall so that the cooling air introduced into the air guiding space57 is rectified toward the introduction path 15 of the compressor body4. In this way, the cooling air introduced into the air guiding space 57through the third air passage 60 is efficiently guided to theintroduction path 15 of the compressor body 4, and satisfactorysupercharging is realized.

In the present embodiment, although the air guiding space 57 is used forsupercharging the outside air from the third air passage 60 to thecompressor body 4, the air guiding space 57 may be also used for coolingthe pressurized gas passing through the discharge pipe 59 similarly tothe above-described embodiment. Since the air guiding space 57 isconfigured to realize a plurality of functions in this manner, it ispossible to reduce a system size and to effectively save an installationspace and a manufacturing cost.

Embodiments of the present invention were described in detail above, butthe present invention is not limited thereto, and various amendments andmodifications may be implemented within a scope that does not departfrom the present invention.

For example, the respective embodiments relate to a so-calledbelt-driven scroll fluid machine in which the driving shaft 22 rotateswith the aid of a power transmission belt that rotates with a dynamicpower source such as a motor or an engine. However, the presentinvention is not limited to the belt-driven scroll fluid machine. Forexample, the present application invention can be applied to a so-calleddynamic-power-source-direct-coupled scroll fluid machine in which therevolving plate 32 is directly connected to one end of the driving shaftof a dynamic power source and the blower fan 52 is fixed to the otherend of the driving shaft.

Moreover, the scroll compressor according to the respective embodimentsis a compressor having the fixed scroll 18 and the revolving scroll 20.However, the present invention is not limited to such a scrollcompressor. For example, the present invention can be applied to ascroll fluid machine including a driving scroll as the first scroll anda driven scroll as the second scroll.

INDUSTRIAL APPLICABILITY

At least one embodiment of the present invention can be applied to ascroll fluid machine.

REFERENCE SIGNS LIST

-   -   1: Scroll compressor    -   2: Filter unit    -   4: Compressor body    -   6: Power transmission unit    -   8: Blower unit    -   10: Filter casing    -   12: Intake port    -   14: Filter element    -   15: Introduction path    -   16: Compressor housing    -   18: Fixed scroll    -   19: Fixed end plate    -   20: Revolving scroll    -   21: Fixed wrap    -   22: Driving shaft    -   23: Eccentric shaft portion    -   24: Radiating fin    -   26: Revolving end plate    -   28: Revolving wrap    -   30: Radiating fin    -   32: Revolving plate    -   33: Rotating bearing    -   34: Rotation prevention mechanism    -   36: Compression chamber    -   37: Bearing portion    -   38: Discharge port    -   40: Driven pulley    -   42: Bearing case    -   44: Ball bearing    -   48: Balance weight    -   50: Fan casing    -   52: Blower fan    -   53: Lid portion    -   54: Duct    -   55: Opening    -   56: First air passage    -   57: Air guiding space    -   58: Second air passage    -   59: Discharge pipe    -   60: Third air passage    -   61: Groove portion    -   63: Cover    -   70: Reinforcement rib    -   80: Convex shape    -   90: Non-contacting region    -   92: Reduced thickness portion    -   95: Cooling fin    -   97: Enlarged diameter portion    -   98: Check valve    -   102: Partition wall    -   104: Low-pressure-side discharge port    -   106: High-pressure-side inlet port    -   110: Intermediate cooler    -   112: Radiating pipe

1. A scroll fluid machine comprising: a housing; a fixed scroll which isfixed to the housing and in which a spiral groove formed by a fixed wrapformed on a fixed end plate is blocked by a partition wall thatpartitions a low-pressure-side compression chamber and ahigh-pressure-side compression chamber; a revolving scroll which isaccommodated in the housing so as to face the fixed scroll to form thelow-pressure-side compression chamber and the high-pressure-sidecompression chamber together with the fixed scroll and is resolvablesupported by a driving shaft; a cover that forms an air guiding spacebetween the fixed scroll and the cover so that a portion of cooling airsupplied to at least one of the fixed scroll and the revolving scrollcan be introduced into the air guiding space; and an intermediate coolerconfigured to cool pressurized gas discharged from the low-pressure-sidecompression chamber by heat exchange with the cooling air in the airguiding space so that the cooled pressurized gas is returned to thehigh-pressure-side compression chamber.
 2. The scroll fluid machineaccording to claim 1, wherein the intermediate cooler includes aradiating pipe arranged in the air guiding space so as to connect alow-pressure-side discharge port of the low-pressure-side compressionchamber and a high-pressure-side inlet port of the high-pressure-sidecompression chamber.
 3. The scroll fluid machine according to claim 2,wherein the radiating pipe is arranged to be folded back on an innerwall of the air guiding space.
 4. The scroll fluid machine according toclaim 3, wherein the radiating pipe is configured such that a pluralityof radiating portion extending along the cooling air are connected by aplurality of folded-back portions formed to be lower than the pluralityof radiating portions.
 5. The scroll fluid machine according to claim 2,wherein the low-pressure-side discharge port is disposed on a downstreamside of the cooling air as compared to the high-pressure-side inletport.
 6. The scroll fluid machine according to claim 1, wherein thescroll fluid machine further includes a discharge pipe through which thepressurized gas discharged from the high-pressure-side compressionchamber flows, wherein the discharge pipe is provided so as to penetratethe air guiding space so that the pressurized gas flowing through thedischarge pipe is cooled by the cooling air introduced into the airguiding space.
 7. The scroll fluid machine according to claim 6, whereina check valve is provided in the discharge pipe.